code: def on_timer(
      self, timestamp, ctx: "KeyedProcessFunction.OnTimerContext"
  ):
      yield "On timer timestamp: " + str(timestamp)
  
file_path: flink/flink-end-to-end-tests/flink-python-test/python/datastream/data_stream_job.py
imports: from typing import Any
  from pyflink.common import Duration
  from pyflink.common.serialization import SimpleStringSchema
  from pyflink.common.typeinfo import Types
  from pyflink.common.watermark_strategy import TimestampAssigner, WatermarkStrategy
  from pyflink.datastream import StreamExecutionEnvironment, TimeCharacteristic
  from pyflink.datastream.connectors import FlinkKafkaProducer, FlinkKafkaConsumer
  from pyflink.datastream.formats.json import JsonRowDeserializationSchema
  from pyflink.datastream.functions import KeyedProcessFunction
  from functions import MyKeySelector
label_desc: Use image node_id 2 for calling the MyProcessFunction obj's underlying member method code with example usage: obj.on_timer(timestamp, ctx) without return types